Sealing strip



Nov. 4, 1958 M. LOUGHBOROUGH 2,358,695

SEALING STRIP Filed June 28, 1957 2 Sheets-Sheet 1 Inventor MA RK LOUGHBOROUGH By.. M 6 4 Attys 7M 1958 M. LOUGHBOROUGH 2,858,695

SEALING STRIP Filed June 28, 1957 2 Sheets-Sheet z FIG. 2

FIG. 3

FIG. 4 20 Inventor MARK LOUGHBOROUGH United States Patent SEALING STRIP Mark Loughborough, Toronto, Ontario, Canada Application June 28, 1957, Serial No. 668,754

I 1 Claim. (31. 72-10 6) This invention relates to a sealing strip, of the type commonly known as a waterstop, which is to be used for preventing the ingress of moisture between adjacent surfaces of concrete slabs or forms which are cast in situ.

Previously proposed constructions of waterstops have had the form, when viewed in transverse cross-section, of a strip which is of materially greater width than thickness, and the strip, when again viewed in transverse crosssection, is provided with localized increases in its thickness, so that the strip is provided with longitudinally extending flutes.

In use, the strip is set up in a mold into which fluid concrete is to be poured for casting the concrete into a predetermined shape with approximately one-half of the width of the strip extending into the mold. The concrete, when poured into the mold, surrounds that portion of the strip extending into the mold to lie in intimate contact therewith, and, when the concrete is set, the sealing strip is anchored in the cast slab or form by the flutes of the strip engaging in the corresponding flutes formed in the concrete. When the concrete is set, the mold boards are removed, and a further set of mold boards are set up adjacent one end of the slab or form for subsequently casting a further slab or form in edge to edge relationship with the previously cast one. I

Considerable difiiculty has been experienced in positioning the sealing strip for it to extend longitudinally of the mold with half its width extending into the mold, due to it being necessary to form a longitudinal slit in the wall of the mold for receiving the strip. This raises problems in the construction of the mold, and results in the mold being of a complicated form with consequent increase in the cost of labour and material.

An object of this invention is to provide a sealing strip of a form which is conducive to ease of assembly of the mold and which renders the provision of a longitudinal slit in the mold walls unnecessary.

Another object of the invention is to provide a sealing strip of relatively simple construction which can be manufactured by extrusion molding.

According to the invention, a sealing strip for use as A a waterstop between adjacent surfaces of concrete slabs or forms, includes, when said strip is viewed in transverse cross-section, three arms arranged in Y formation.

According to a further feature of the invention, at least one of the arms is provided with local increases in its thickness, whereby flutes are formed extending longitudinally of said strip.

Further features of the invention will be appreciated from a study of the following specification when taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a perspective view of a preferred form of sealing strip according to the invention and showing the transverse cross-section of the strip;

Fig. 2 is a cross-section through a mold when filled with concrete, and showing the sealing strip according to the invention located within the mold;

Referring to Figure 1, the sealing strip when viewed in transverse cross-section has three arms 10, 11, 12, arranged in Y formation, the arms 11 and 12 of which subtend an acute angle, and the arm 10 of which substantially bisects the obtuse angle subtended the arms 11, 12. As will be seen, the arms are integral with each other at a common junction at 13, the transition from one arm to the other being through a smooth radius.

The sealing strip is preferably formed from natural or synthetic rubber, or some suitable synthetic resin or plastic of the types commonly known as elastomeric, although the strip may if desired be formed from a ductile material for example aluminum or copper in which case the thickness of the arms would be materially reduced to facilitate bending of the arms for a purpose hereinafter referred to.

Referring now to Fig. 2, the sealing strip is secured in position in the mold by splaying the arms 11 and 12 and by securing the strip to a wooden end wall 14 of the mold by means of tacks 15. The tacks penetrate into the end wall to an extent sufiicient to locate the sealing strip thereon without securely fixing the strip to the wall, the strip being secured in position prior to the end wall being placed in its appropriate position in the mold.

With the end wall in position, it will be observed that the arm 10 extends into the cavity of the mold in such a manner that it can be surrounded, as is indicated at 16, by concrete when in a fluid state, the concrete being contained by said walls 18 of the mold and the end wall 14.

When the concrete has set, the walls 14 and 18 are removed, the tacks 15 during this procedure pulling out of the end wall 14 to release the arms 11 and 12 of the sealing strip.

At this point the concrete slab or form has the appearance of that shown in Figure 3, the arm 10 being securely fixed in the concrete by reason of the intimate contact of the concrete with the side walls thereof, and the arms 11, 12 having returned to their original position due to their inherent resiliency. As the arms move to their original position, they leave behind cavities 11a, 12a, these cavities forming a very effective keyway when a further concrete slab is cast in end to end relationship with the presently formed one. Where the strip is formed from a material which is not resilient, the arms 11, 12 are moved manually to the position shown in Figure 3.

A further mold is then erected, as indicated in Figure 4, and fluid concrete is poured into the cavity formed by the walls 20, 20 so that it surrounds the arms 11 and 12, as is indicated at 16a.

Thus, two concrete slabs or forms are formed with their edges in abutting relationship, the arm 10 of sealing strip being securely embedded in the slab 16 While the arms 11 and 12 are securely embedded in the slab 16a, the edges of the slabs being keyed together at their mating surfaces 16b.

Where it is contemplated that there will be movement of the slabs 16 and 16a due to thermal expansion, a suitable compressible material would be applied to the end of the slab 16 prior to casting the slab 16a. In this case it is preferable to use a sealing strip which is of the form shown in Figure 5, the difference being that a longitudinal bore 21 is provided through the junction 13, so that, should the slabs 16 and 16a expand to close the gap between them, the material from which the sealing strip is formed will be displaced into the bore.

It will be seen that by the invention a simple and effective sealing strip has been provided in which the necessity for providing a longitudinal slit in the end wall 14 of the mold is avoidedjand with it consequent complications in the construction of the mold,

' What I claim as my'invention is:

A sealingstrip for incorporation in adjacent monolithic concrete structures to effect a watertight seal therebetween, comprising, a strip of elastomeric material, the transverse sectional'shape of said strip comprising three substantially straight arms of approximately equal length and integrally joined at a common junction, said strip being self-sustaining with said arms in Y-formation, two of said arms subtending an acute angle, the third arm substantially bisecting the angle between said two arms, said material being sufficiently flexible to permit said two arms to be spread apart to lie in a common plane substantially perpendicular to the plane of the third arm whereby to lie against an inner face of a mold with said third arm extending into said mold to be embedded in concrete cast therein, said strip being sufli'ciently elastic so that said two arms return to said Y-formation upon removal of said mold, each of said arms having integral keying means on the faces thereof for keying said strip in place when embedded in concrete.

References Cited in the file of this patent UNITED STATES PATENTS 2,431,104 Bright Nov/18, 1947 FOREIGN PATENTS 1,074,307 France of 1954 

